Urinary excretion of 13 dietary flavonoids and phenolic acids in free-living healthy subjects – variability and possible use as biomarkers of polyphenol intake

Abstract

Objective: Estimation of dietary intake of polyphenols is difficult, due to limited availability of food composition data and bias inherent to dietary assessment methods. The aim of the present study was to evaluate whether we could detect polyphenols and their metabolites in a spot urine sample in a free-living human population and whether it was related to those observed in 24-h urine samples, for potential use as a biomarkers of polyphenol intake. Subjects: Four 24-h urine samples and two spot urine samples were collected from 154 participants of the SU.VI.MAX cohort (a randomized primary-prevention trial evaluating the effect of daily antioxidant supplementation on chronic diseases) in two separate studies over, respectively, a 7-and 2-day periods. Thirteen polyphenols and metabolites (chlorogenic acid (CGA), caffeic acid (CA), m-coumaric acid (mCOU), gallic acid (GA), 4-O-methylgallic acid (MeGA), quercetin (Q), isorhamnetin (MeQ), kaempferol (K), hesperetin (HESP), naringenin (NAR), phloretin (PHLOR), enterolactone (ENL) and enterodiol (END) were measured using HPLC-ESI-MS-MS. Results: Correlations between the urinary excretion levels were observed. The most significant were explained by metabolic filiations (CGA/CA, CA/mCOU, GA/MeGA, Q/MeQ, NAR/PHLOR, ENL/END) or co-occurrence in a same food source (NAR/ HESP). Concentrations in spot samples correlated with those in 24-h urine sample (Po0.02, except for CA and for MeQ). Intraindividual variations were smaller than inter-individual variations for all polyphenols (Po0.01) except for MeGA and for PHLOR. Conclusion: These results show that these polyphenols and metabolites are useful biomarkers for polyphenol intake.

The complex links between dietary phytochemicals and human health deciphered by metabolomics

“…Thirteen polyphenols have been estimated in both spot urine samples and 24-h urine samples collected by 154 subjects following their regular diets. Good correlations were observed between most polyphenols and the consumption of their major food sources in both types of urine samples [59]. The phytochemicals most quickly excreted might be under-represented in urine or plasma collected in fasting conditions.…”

“…The phytochemicals most quickly excreted might be under-represented in urine or plasma collected in fasting conditions. However, good correlations between intake of various polyphenols and concentrations in spot urine samples collected in fasting conditions have been observed [59].…”

Improving the Bioavailability of Polyphenols

“…Recently, highly sensitive tandem mass spectrometry (MS) studies have addressed this issue and have been reviewed by many authors (Prasain and Barnes, 2007). Mennen et al (2008) have recently challenged our whole understanding of the benefi cial health effects of dietary fl avonoids, by targeting several polyphenols and their metabolites in a spot of urine as the biomarker of polyphenol intake.…”

Fruits and vegetables: measuring intake and encouraging increased consumption

“…Six carotenoids (a-carotene, b-carotene, b-cryptoxanthin, zeaxanthin, lycopene and lutein) are found in appreciable amounts in human serum (65,70) . Other candidate biomarkers of FV intake include antioxidant vitamins such as vitamin C (71,72) and flavonoids (73,74) , including quercetin (75) . Some of these compounds have been reliably associated with a particular fruit or vegetable, or a class of FV in observational studies, but less successfully with total FV consumption (69,70,72,(76)(77)(78)(79)(80) .…”